The present embodiments relate to medical ultrasound imaging. In particular, stress echocardiography is performed within a limited time window after ending the stress on the patient.
Stress echocardiography evaluates cardiac function by studying the cardiac wall motion and thickness in response to stress caused by physical exercise or medical agents. During exercise echocardiography, the patient exercises on a treadmill or a bicycle machine until their heart rate reaches a targeted level. Imaging during exercise (e.g., on a treadmill) may not be feasible. Because exercise induced abnormal wall motion only lasts for a short amount of time, images have to be acquired immediately after the cessation of exercise. The duration of exercise-induced abnormal wall motion is patient dependent and generally less than three minutes after the cessation of exercise. The American Society of Echocardiography recommends image acquisition within one to two minutes after the cessation of exercise, while the European Association of Echocardiography recommends less than one minute.
In practice, the protocol varies from one health provider to another, with the duration of post stress imaging arbitrarily set from one to ten minutes post-stress image acquisition. When a protocol uses a very short duration, for example within 1 minute after the cessation of exercise, obtaining quality data is challenging. When a protocol uses a longer duration, a large amount of data may be useless or less useful. Images acquired after the heart rate has dropped low enough show no or little abnormal wall motion.